Diurnal Ocular Perfusion Pressure Research Articles

A comparative analysis of the postural and diurnal ocular perfusion pressure of young healthy individuals of different ethnicities

Purpose: Ocular perfusion pressure (OPP) regulates the flow of blood to the optic nerve and is determined by the interaction between intraocular pressure (IOP) and blood pressure (BP). Low OPP increases the incidence of primary open-angle glaucoma (POAG). The aim is to compare the diurnal (i.e. morning vs. afternoon) and postural (i.e. seated vs. supine) OPP in healthy individuals from different ethnicities aged between 18 and 30 years. Methodology: Averaged IOP and BP measurements were obtained with an ICare rebound tonometer and an automated sphygmomanometer, respectively. Measurements were taken in the morning and afternoon, in the supine and seated positions in healthy young adults: Africans ( n = 10), white people ( n = 10), mixed-race people ( n = 10) and Indians ( n = 10). Results: The whole sample ( N = 40) displayed a statistically significant reduction in postural and diurnal OPP both in the supine position and in the morning, respectively. A comparative analysis revealed that Africans displayed statistically significant reduction in OPP when compared to other ethnicities. Discussion: A change in posture to the supine position has a greater impact on the reduction of OPP when compared to diurnal changes. Africans displayed clinically significant reduction in OPP which may increase the incidence of POAG in this ethnicity at an early age. Conclusion: Our findings question whether OPP should be considered as a biomarker in the dark-skinned individuals. An evaluation of BP and IOP in the supine position is recommended for all patients to obtain more conclusive readings.

Latanoprostene Bunod, a Dual-acting Nitric Oxide Donating Prostaglandin Analog for Lowering of Intraocular Pressure

Current topical treatments for glaucoma have limited efficacy in lowering intraocular pressure (IOP) and/or can produce side effects and tolerability problems. At present, IOP remains the only known modifiable risk factor to delay the progression of glaucoma. The novel IOP-lowering treatment latanoprostene bunod (LBN) is a nitric oxide (NO)-donating prostaglandin F2αanalog that is rapidly metabolized in situ to latanoprost acid and butanediol mononitrate, an NO-donating moiety. LBN has a dual action in that it enhances aqueous humor outflow via both the uveoscleral and trabecular meshwork pathways. It is undergoing regulatory review by the Food and Drug Administration (FDA) for the reduction of IOP in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). In the dose-ranging VOYAGER study, LBN 0.024%, the lower of the most effective concentrations evaluated, demonstrated significantly greater IOP lowering and comparable side effects compared with latanoprost 0.005%. The recent APOLLO phase III clinical study (n=420) found LBN 0.024% demonstrated significantly greater reductions in IOP than timolol 0.5% in patients with OAG or OHT at various time points over 3 months. The same study found the proportion of patients with IOP ≤18 mmHg was significantly greater with LBN 0.024% than with timolol 0.5%. In the LUNAR study (n=420), LBN 0.024% was non-inferior to timolol 0.5% over 3 months’ treatment. LBN treatment also resulted in significantly greater IOP lowering than timolol at all time-points with the exception of the first post-baseline assessment. In JUPITER, a study of 130 subjects with OAG or OHT, LBN 0.024% was safe and well tolerated when used for up to a year, and provided significant and sustained IOP reduction. Further, in CONSTELLATION, a study of 25 patients with OHT or OAG, IOP lowering with LBN 0.024% was consistently lower than baseline during both the diurnal/wake and nocturnal/sleep periods whereas timolol 0.5% reduced IOP only during the diurnal period. In addition, LBN 0.024% treatment resulted in a significantly increased diurnal ocular perfusion pressure versus baseline and nocturnal ocular perfusion pressure versus timolol 0.05%. Similarly, in KRONUS, a single-arm, single-center, openlabel study of 24 healthy Japanese subjects, LBN 0.024% significantly lowered mean IOP over a 24-hour period. Across these studies, LBN has demonstrated a favorable safely profile and good ocular tolerability. It is hypothesized that LBN’s dual action on the outflow pathways accounts for the improved efficacy when compared with latanoprost and timolol.

Twenty-four-hour efficacy of preservative-free tafluprost for open-angle glaucoma patients, assessed by home intraocular pressure (Icare-ONE) and blood-pressure monitoring.

To evaluate the effect of preservative-free (PF) tafluprost on diurnal variation of intraocular pressure (IOP) and ocular perfusion pressure (OPP), measured by use of home IOP and blood-pressure (BP) monitoring devices, for primary open angle glaucoma (POAG) patients. Twenty-two eyes from 22 patients with POAG were studied. Initially, IOP was measured at the hospital by Goldmann applanation tonometry (GAT) and Icare-ONE rebound tonometry. Each patient was then instructed how to use the Icare-ONE and BP home monitoring devices. IOP and BP were measured at home by the patients, every 4 h, before and 2 weeks after once daily treatment with PF tafluprost (0.0015%) ophthalmic solution. Intraclass correlations between different IOP measurements were greater than 0.8. PF tafluprost reduced mean diurnal IOP significantly for patients with POAG, from 15.7 ± 1.2 mmHg at baseline to 12.5 ± 0.6 mmHg 2 weeks after treatment (p < 0.001). It increased mean diurnal OPP from 48.5 ± 7.3 mmHg at baseline to 51.3 ± 7.0 mmHg post-treatment (p < 0.017). Icare-ONE enables glaucoma patients to measure their own diurnal IOP fluctuations. Patient-measured Icare-ONE IOP readings showed that PF tafluprost effectively reduced diurnal IOP in eyes with POAG.

Twenty‐four‐hour rhythm of ocular perfusion pressure in non‐arteritic anterior ischaemic optic neuropathy

In non-arteritic anterior ischaemic optic neuropathy (NAAION) patients, circulatory insufficiency within the optic nerve has previously been hypothesized to be related to nocturnal systemic hypotension. The main objective of this prospective cohort study was to investigate the nyctohemeral variations in ocular perfusion pressure (OPP) in NAAION patients. In 20 patients with NAAION, the intraocular pressure (IOP) was measured using the Tono-Pen XL(™) electronic tonometer every hour for 24 hr. Blood pressure (BP) was evaluated over 24 hr. Mean OPP was calculated with the following formula: OPP sitting position = (0.74 × mean BP) - IOP and OPP lying position = (0.84 × mean BP) - IOP. A nonlinear least squares dual-harmonic regression analysis approach was used to model the 24-hr rhythms of OPP data. On average, a 24-hr amplitude of 4.7 ± 2.6 mmHg was found for OPP. The patients were classified as either having a diurnal OPP rhythm (i.e. with a diurnal acrophase, 10% of the cases), a nocturnal OPP rhythm (45%) or absence of OPP rhythm (45%). Four patients had a nocturnal reduction in OPP (mean, -11%). The physiological nocturnal rhythm of OPP was maintained in 45% of the NAAION patients. The nocturnal reduction in OPP seen in 20% of the patients was within the range of OPP where optic nerve blood flow autoregulation is still fully operative. A high prevalence of obstructive sleep apnoea syndrome in our population (71%) may explain the low frequency of systemic nocturnal hypotension.

Relationship of systemic blood pressure with ocular perfusion pressure and intraocular pressure of glaucoma patients in telemedical home monitoring

SummaryBackgroundWe evaluated the relation of systemic blood pressure with intraday variations in ocular perfusion pressure and intraocular pressure in patients with primary open-angle glaucoma in a telemedical home monitoring scenario.Material/MethodsIn the project Teletonometry Mecklenburg-Vorpommern (TTMV) patients were equipped with a home monitoring system for 24-hour self-measurements of intraocular pressure and blood pressure for a period of six months. All measurements were transmitted via telephone modem to an electronic patient record. Ocular perfusion pressure (OPP) was automatically calculated from self-measurements of intraocular pressure (IOP), systolic (SBP) and diastolic blood pressure (DBP) using the equation: OPP=[2/3*(2/3*DBP+1/3*SBP)]–IOP. We present the temporal characteristics of 70 patients with primary open-angle glaucoma based on 3282 self-measurements.ResultsThe diurnal ocular perfusion pressure trend showed four characteristic phases (7am – 12am, 12am – 6pm, 6pm – 10pm, and 10pm – 7am). Between 7am and 12am ocular perfusion pressure and simultaneously systolic and diastolic blood pressure were significantly depressed compared to all other phases (p<0.05) whereas intraocular pressure showed no significant shifting. Instead intraocular pressure was significantly depressed between 6pm and 10pm (p<0.05) where ocular perfusion pressure reached the highest intraday values.ConclusionsWe found that ocular perfusion pressure in patients with primary open-angle glaucoma showed remarkable circadian fluctuations. A significant decrease in the morning was associated with significantly depressed systolic and diastolic blood pressure levels. In addition we observed normal intraocular pressure values in the morning but a significant decrease in the evening which did not affect ocular perfusion pressure. These conclusions strengthen the evidence that systemic blood pressure fundamentally influences ocular circulation and consequently glaucoma progression.

The additive effect of dorzolamide hydrochloride (Trusopt) and a morning dose of bimatoprost (Lumigan) on intraocular pressure and retrobulbar blood flow in patients with primary open-angle glaucoma

AimsTo assess the additive effect of dorzolamide hydrochloride 2% on the diurnal intraocular pressure (IOP) curve and retrobulbar haemodynamics in patients with primary open-angle glaucoma (POAG) treated with morning-dosed bimatoprost...

Tagesschwankungen des okulären Perfusionsdrucks im Telemonitoring bei primärem Offenwinkelglaukom

The aim of this study was to study and analyse distribution, range and intraday variation of ocular perfusion pressure (OPP) in patients with primary open-angle glaucoma (POAG) in the framework of telemedical home-monitoring. In the project Teletonometry Mecklenburg-Vorpommern (TTMV) patients were equipped with a home-monitoring system for self-measurement of intraocular pressure and blood pressure. All measurements were transmitted via telephone modem to an electronic patient record that automatically calculated OPP. We present the temporal characteristics of OPP in 70 patients with POAG. After the measurement of blood pressure and intraocular pressure was performed, the individual ocular perfusion pressure was calculated by the formula: (OPP=[2/3 x (2/3 x DBP + 1/3 x SBP)]-IOP). In 3282 OPP measurements the percentage of values less than 50 mmHg was: left eye 2273/69.2%--right eye 2362/71.9 % and less than 40 mmHg: left eye 687/20.9 %--right eye 794/24.2%. 50/51 (left eye/right eye) patients had an individual OPP average of less than 50 mmHg and 10/10 (left eye/right eye) patients less than 40 mmHg. The diurnal OPP trend showed 4 phases (7-12, 12-18, 18-22, 22-7 hour). In the intervals from 22-7 hour and 7-12 hour ocular perfusion pressure values were low. Between 7-12 hour ocular perfusion pressure was significantly depressed as in the other phases (p<0.05). Ocular perfusion pressure of glaucoma patients calculated using intraocular pressure (self-tonometry) and blood pressure demonstrates a feasible method to evaluate individual diurnal OPP fluctuations. However, this OPP could be described a bit more precisely as the really topical ocular perfusion. Many physiological conditions may not be included, e. g., autonomic circulation. Simultaneous measurement of blood pressure and intraocular pressure enable the detection and analysis of side effects and interactions between glaucoma and hypertension therapy. In clinical practice OPP telemonitoring presents a new way to examine ocular blood circulation in routine glaucoma work-up. The diurnal OPP variations were associated with the fluctuations of systemic blood pressure for the most of part.

Effect of Latanoprost on the Diurnal Variations in the Intraocular and Ocular Perfusion Pressure in Normal Tension Glaucoma

To evaluate the effects of latanoprost on the diurnal variations in the intraocular pressure (IOP) combined with the ocular perfusion pressure (OPP) in patients with normal tension glaucoma (NTG). Twenty-two eyes from 22 patients with NTG were used for the study. The diurnal variations in the IOP and blood pressure (BP) were measured every 3 hours without therapy, and then the patients were treated with latanoprost (0.005%) once daily for more than 12 weeks. The diurnal variations in the IOP and BP under medication were again measured every 6 hours. The diurnal variation of IOP for 24 hours, mean diurnal IOP, maximum IOP, minimum IOP, range of variation in IOP, OPP, and BP were compared between the baseline and after treatment by means of a paired t test. At 3 months after the start of the latanoprost treatment regimen, the IOP showed a statistically significant decrease at every assessed time point over 24 hours (P<0.001). Latanoprost significantly reduced the mean diurnal IOP, maximum IOP, minimum IOP, and mean range of variation in the IOP values from baseline (P<0.001, <0.001, <0.001, and 0.009, respectively). OPP after treatment showed no significant difference at any assessed time points from the baseline (P>0.1). Latanoprost did not significantly alter the mean diurnal OPP (P>0.1), and BP (P>0.5) from the baseline. Latanoprost was thus found to significantly reduce IOP over 24 hours, whereas it does not affect OPP and BP in NTG patients. Therefore, it may be a useful medication for NTG.